Rotary compressor injection cooling arrangement



- Nov. 5, 1963 D. c. RINEHART 3,109,297

ROTARY COMPRESSOR INJECTION COOLING ARRANGEMENT Filed Sept. 20, 1961 2 Sheets-Shem: 1

F'IGJ INVENTOR. DEAN C. RINEHART H s ATTORNEY N V- 1953 D. c. RINEHART ,1

ROTARY COMPRESSOR INJECTION COOLING ARRANGEMENT Filed Sept. 20, 1961 2 Sheets-i-Sheei: 2

PIC-3.3

INVENTOR. DEAN c. R\NEHART' BYMW HIS ATTORNEY United States Patent 3,109,297 ROTARY COMPRESSOR INJECTION CGQLING ARRANGEMENT Dean C. Rinehart, Louisville, Ky., assignor to General Electric Company, a corporation of New York Filed Sept. 20, 1961, Ser. No. 139,447 6 Claims. (Ci. 62-197) The present invention relates to rotary compressors and more particularly to an arrangement for supplying condensed liquid refrigerant to the compression chamber of a rotary compressor for cooling the gases during the compression thereof.

It is common practice in the field of refrigeration to mount both the refrigerant compressor and its drive motor within a hermetically sealed casing. In such an arrangement it is necessary to provide some means for cooling the drive motor in order to maintain its temperature within safe operating limits. One means employed for this purpose is to pass the high pressure discharge gas from the compressor unit over the compressor motor after the high pressure gas has been cooled to a low enough temperature to remove heat from the motor thereby maintaining the motor at a safe operating temperature. The heat removed -from the motor is carried olf by the gas and dissipated in the condenser of the refrigerating system. This is an efficient method of maintaining the motor at a proper operating temperature but requires that the high pressure discharge gas be precooled before being passed into intimate contact with the motor.

One arrangement for precooling the high pressure gas is to first pass this gas through a superheat removal coil which is connected to the discharge outlet of the compressor unit and extends outside the hermetic casing into the outside ambient. The high pressure gas then flows directly from the compressor into the superheat removal coil and is cooled before being passed back into the case and over the motor. The incorporation of a superheat removal coil onto the hermetic casing creates a sealing problem and, in addition, the intermittent discharge pulses of high pressure gas flowing through the superheat removal coil sometimes causes audible vibrations that are transmitted by the coil to the supporting structures of the air conditioning unit.

Another arrangement for cooling the discharge gas within the hermetic case is to introduce liquid refrigerant into the hermetic case from a source of condensed refrigerant in the refrigeration system. The liquid refrigerant expands into a gas and mixes with and cools the high pressure gases in the case which then cool the motor prior to discharging into the remaining portions of the system. However, in order to withdraw condensed refrigerant from the condenser or other portions of the refrigeration system, it is necessary to overcome the pressure drop in the system which occurs in the tubing between the compressor and the condenser. Some means, must be provided for reducing the pressure at the outlet of the liquid supply conduit in order to obtain flow of refrigerant from the condenser into the hermetic casing.

Accordingly, it is an object of the present invention to provide in a compressor utilizing high pressure discharge gas for motor cooling purposes an improved arrangement for injecting condensed refrigerant into the high pressure gas before passing this mixture over the compressor drive motor.

It is another object of the present invention to provide an improved arrangement whereby liquid refrigerant, is

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sufliciently below discharge pressure to permit injection thereof without greatly diminishing the capacity of the compressor.

A more specific object of the present invention is to provide an improved arrangement for injecting liquid refrigerant through a port opened and closed by the rotor within the compression chamber of a rotary compressor and for reducing the noise pulsations caused by the opening and closing of the injection port by the rotor.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In carrying out the objects of the present invention there is provided a hermetically sealed refrigerant gas compressor unit adapted to form a part of a refrigerating system including a condenser for condensing the refrigerant compressed by the compressor unit and an evaporator for evaporating the condensed refrigerant. The compressor unit and its drive motor are mounted within a hermetically sealed case into which the compressor unit discharges its compressed refrigerant which flows over the motor prior to passing into the condenser of the refrigeration system. The compressor unit includes a cylinder having an annular compression chamber and end walls enclosing opposite sides of the chamber. An annular rotor is mounted within the chamber and is driven in an eccentric motion around the chamber by a shaft extending from the motor through one end wall of the chamber. The peripheral surface of the rotor moves progressively into sealing engagement with successive portions of the annular chamber during rotation and drives gas around the chamber. A radial slot, formed in the cylinder, carries a reciprocable blade which is biased into engagement with the peripheral surface of the rotor thereby dividing the chamber into high and low pressure sides during rotation of the rotor. Means, including a suction port formed in the cylinder, direct suction gas into the low pressure side of the chamber and means, including a discharge port in the cylinder, discharge compressed gas from the high pressure side of the chamber into the casing where the gas then flows over the motor for cooling purposes. In order to maintain the discharge gas at a sufficiently low temperature to properly cool the motor, there is provided a liquid refrigerant injection port in one end wall of the chamber which is uncovered and covered during each cycle of rotation of the rotor around the chamber. A liquid refrigerant supply passage leading from a suitable source of condensed liquid refrigerant, such as is found in the condenser of the system, delivers liquid refrigerant to the injection port where it is injected into the chamber during each cycle of the rotor to expand and mix with the gas being compressed therein thereby reducing the temperature of the high pressure gas discharging from the chamber.

As a further aspect of the invention, means are provided in the liquid refrigerant supply passage for damping liquid impulses or vibrations created in the liquid passage by the intermittent opening and closing of the injection port. These liquid impulses are damped in an expansion chamber, or gas trap, formed in the lower region of the hermetic case and surrounded by oil which collects in the lower portion of the casing. The oil heats the liquid refrigerant within the expansion chamber and creates a compressible gas pocket within the chamber which clamps the impulses as they are conducted hack through the passage from the injection port thereby preventing these impulses or vibrations from being carried through the liquid supply passage into the remaining portions of the system.

amaze? For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIGURE 1 is a side elevation view partially in section of a hermetic refrigeration compressor incorporating the present invention;

FIGURE 2 is a partial plan view taken along line 2-2 of FIGURE 1;

FIGURE 3 is a schematic view of a refrigeration system including a compressor of the present invention; and

FIGURE 4 is a schematic view illustrating the angular positions of the rotor when the liquid refrigerant injection port is opened and closed by the end of the rotor.

Referring to FIGURE 1 of the drawings, there is shown a hermetic compressor 1 including a hermetic casing 2 in which there is disposed a refrigerant compressor unit 3 having an annular chamber or compression chamber 4 defined within a cylinder or housing 5. Disposed for rotation within the chamber 4 is a rotor 6, which is driven by an eccentric '7, formed as an integral part of the drive shaft 8 extending downwardly from the motor 9. A bearing 11, which with the supporting main frame 12, defines the upper end wall of the annular compression chamber 4 of the cylinder, supports the shaft 8 above the eccentric 7 for rotation by the motor. The main frame 12 also supports the compressor unit 3 within the casing. The opposite or lower end wall of the chamber 3 is formed by a bearing plate It] which also supports the lower end of the shaft 8 in a bearing lltta.

As may better be seen in FIGURE 2, the cylinder is provided with a radial slot 13 having slidably disposed therein a blade or vane 14- which is biased into engagement with the peripheral surface 60: of the rotor 6 thereby dividing the chamber 4 into low and high pressure sides respectively designated 4a and 4b. In the illustrated embodiment of the invention, the end of the blade 14 is biased against the periphery of the rotor by means of a spring 16 arranged within an enlarged opening 13a forming the rear part of the radial slot 13. During operation of the unit, the rotor 6 is eccentrically rotated within the chamber by the eccentric 7 so that the peripheral surface 6a of the rotor moves progressively into sealing relation with the successive portions of the annular chamber thereby forcing gas ahead of it in the direction of rotation in the manner well known in the art so that gas is compressed in the diminishing space bounded by the ends of the chamber, the rotor periphery 6a and the high pressure side 14a of the vane.

As may be seen in FIGURE 3, the hermetic compressor 1 is adapted to be connected into a refrigeration system to receive suction gas from an evaporator through a suction line 29. Means are provided for delivering the suction gas into the low pressure side 4a of the annular chamber 4a from the suction line 20. Morespecifically, again referring to FIGURE 2, these means include a suction port 17 formed in the cylinder 5 and communicating with the annular chamber 4. The suction port 17 delivers low pressure gas into the low pressure side 4a of the compression chamber 4 where it is compressed between the peripheral surface of the rotor 6, the sides of the annular chamber, and the high pressure side 14a of the vane 14 during rotation of the rotor 6 around the chamber.

Means including a discharge port 18 and a discharge chamber 19, are provided for directing the high pressure gas from the high pressure side 4a of the annular chamber 4 into the hermetic casing 2. Mounted within the discharge chamber 19 is a suitable valve 21 for assuring proper compression of the gas issuing from the discharge port 18 and for preventing reverse flow of gas back into the compression chamber 4. As may be seen in FIG- URE 1, the high pressure gas from the discharge chamber 19 flows into the hermetic case 2 through a passage 25 in the main frame 12 which forms the upper end wall of the compressor unit. After flowing upwardly over the motor 9, the high pressure gas is conducted out of the hermetic casing 2 through a suitable discharge means or outlet (not shown) in the upper end of the case and flows through the discharge line 21 (shown in FIGURE 3) into the condenser 22 where the heat, absorbed by the refrigerant in the other portions of the system, is extracted. As the gas in the condenser 22 is cooled, it com denses so that the refrigerant in the latter stages of the condenser is largely in liquid form. A suitable expansion means is provided between the condenser and the evaporator for expanding the liquid refrigerant from condenser pressure to evaporator pressure during operation of the system. In the illustrated embodiment of the invention, the expansion means comprises a capillary 23 located between the condenser and the evaporator of the system.

Referring again to FIGURE 1, there is shown an arrangement whereby lubricating oil is provided for the various bearing surfaces and other moving parts of the unit. More specifically, there is a reservoir or body of lubricant 24 in the lower portions of the hermetic casing. This body of lubricant or oil is of sufiicient depth that the lower end of the shaft 8 and a portion of the lower end wall 10 of the compressor unit are substantially immersed in the lubricating oil. Means are provided for pumping lubricant to the various moving parts of the compressor unit. More specifically, there is provided a relatively large axially extending passage 26 in the shaft 8. The axially extending passage 25 is in communication with the reservoir 24 and, upon the rotation of the shaft, lubricant entering the axial passage 26 is forced to quickly assume the rotational speed of the shaft 8. Centrifugal force then causes the lubricant to flow outwardly against the inner surface of the axial passage 26 and upwardly along the inner passage. Oil outlets provided along the circumference of the shaft transmit lubricant to the various bearings of the compressor. Oil return passages 27 and 28 in the bottom plate, 10 and in the main frame 12 respectively provide means for returning excess oil to the oil sump 24 in the lower regions of the case. Because the oil within the case is constantly flowing over the compressor and motor of the unit, it will be understood that the oil in the sump 24 is relatively hot.

In a compressor of the type described above, when tested in a refrigeration system having air at approximately F. blown over the evaporator 15 and F. air blown over the condenser 22, the pressure of refrigerant gas within the hermetic case was approximately 300 p.s.i.g. The pressure within the high pressure side 41) of the annular chamber reached a maximum of 330 p.s.i.g. The suction pressure in such a refrigeration system normally runs approximately 225 p.s.ig less than discharge pressure or about 75 p.s.i.g. and thetemperature of the suction gas is approximately 60 to 70 F. Of course, the various applications of the above compressor and the particular design features of the refrigeration system all effect the pressure of the gas within the case. But, as can be seen from the above representative figures, the pressure within the hermetic case 2 is substantially above that of suction pressure. As the suction gas is compressed Within the chamber 4 from 75 p.s.i.g. to 330 p.s.i.g. there is a substantial increase in temperature of this gas during compression. For example, in the above described refrigeration system, the gas temperature is increased from approximately 75 or F. to 200 or 250 F. whiolnunder most conditions of operation, is too hot to carry the motor heat away at a rate calculated to maintain proper motor operating temperatures. Thus, if the gas is permitted to discharge at this high temperature, there is likely to be insufiicient cooling of the motor 9 and damage to the motor insulation or windings is likely to occur.

.uis passed thereover, the present invention provides means for injecting a small quantity of liquid refrigerant into the compression chamber 4 during each compression cycle of the rotor thereby reducing the ultimate temperature of the discharge gas. More specifically, there is provided an injector port 31 arranged on the high pressure side 4b of the compression chamber 4. In the preferred embodiment of the invention, this port 31 is arranged with respect to the high pressure side 4b of the compression chamber 4 and with respect to the rotor 6 so that the end 32 of the rotor 6 completely covers the port 31 at all times during each cycle of the rotor except for a short period during each cycle when the gas pressure in the high pressure side 4b of the compression chamber 4 is between 50% and 95% of discharge pressure.

As may be seen in FIGURES 1 and 3, means are provided for introducing liquid refrigerant into the injector port 31 from a source of condensed refrigerant in the refrigeration system. More specifically, there is provided a liquid refrigerant supply passage which connects with the latter stages of the condenser 22 of the system and conducts liquid or condensed refrigerant from the condenser to the injector port 31. As may be seen in FIG- URE l, the passage includes the conduit or line 33 and the larger tube 34- which enters the case 2 and passes upwardly through the oil sump 24 where it is attached to the "bottom plate It) by means of a connecting stud 35 arranged in alignment with the injector port 31. A small capillary or tube 36 extends from the center of the stud 35 into the lower regions of the tube 34- where it is constantly immersed in liquid refrigerant in the tube 34 and completes the liquid refrigerant supply passage to the injector port 31. It will be noted that the opening between the tube 33 and the tube 36 permits liquid refrigerant to flow into the larger tube 34. Thi arran ement provides a liquid refrigerant reservoir covering the end of the tube 36 and creates a refrigerant gas trap or expansion chamber 36:: within the larger tube 35. The expansion cha .ber 3oz: serves to damp vibrations or liquid impulses created by the intermittent opening and closing of the injection port 31 during the rotation of the rotor, as will be more fully described later on in the specification.

Referring now to the schematic diagram of FIGURE 4. it may be seen that the injection port 31 is closed at all times during cycle of the rotor 6 except during the period when the contacting or peripheral surface 6a of the rotor moves from point A to point C of the annular chamber. As will be noted in FIGURE 4, the location of the injection port 31 of the illustrated compressor is adjacent the high pressure side i451 of the blade E4 on a line passing through the center of the chamber and at an angle or" approximately 12 with respect to the center line of the blade 14. At point A the end 32 of the rotor is just beginning to uncover the liquid injection port 31 and at point C it has again closed the port.

In the illustrated embodiment of the invention, the location of the point A is approximately 245 in advance of the completion of the compression stroke or in advance of the center line of the blade 14. In a tested compressor unit having the relative dimensions of the compressor shown in the drawings, the pres ure of the gas within the high pressure side 4!) of the chamber, when the rotor surface 60 was at point A, was approximately 160 p.s.i.g. or approximately 50% of the pressure of the gas Within the case. Point C is located approximately 140 in advance of the completion of the compression stroke or in advance of the center line of the blade 14. When the rotor of the tested compressor was in the position indicated by point C, the pressure within the high pressure side 4b of the chamber was approximately 290 p.s.i.g., which is about 93% of the pressure within the case 2. In order to prevent reverse flow of gas through the injection port 31, it should be located so that it is completely covered by the end 32 of the rotor 6 when the pressure in the chamber exceeds that of the case or exceeds that within the condenser, which is only slightly below the pressure within the case. The average pressure of the gas, within the high compression side 4b of the chamber 4 in the tested compressor, was about 225 p.s.-i.g. during that portion of the cycle when the liquid injection port 31 was unsealed. This is only an average of 75 p.s.i.g. below discharge pressure and although it permits some expansion or flashing of the liquid refrigerant being injected into the expansion chamber to cool the gas being compressed therein, it does not too greatly affect the etliciency of the compressor. It will be noted from FIGURES 2 and 4, that at all times during injection of refrigerant into the compressor the suction port 17 is closed. That is, the peripheral surface 6a in contact with the annular chamber 4- has moved past the edge 17a of the suction port 17 and has completely sealed the suction port before the injection port 31 is uncovered. Thus, all of the suction gas trapped in the high pressure side 4b of the chamber is within the chamber at the time that the liquid refrigerant is injected therein for cooling purposes.

During each compression cycle, when the cooled liquid refrigerant, injected into the chamber 4, encounters the relatively hot semi-compressed gas in the chamber 417, it vaporizes or flashes into gaseous form. Heat removed from the semicompressed gas in vaporizing the liquid refrigerant to gaseous form greatly reduces the temperature of the gas within the chamber 45 so that the result ant gas issuing through the discharge port 18 and through the passage 25 is at a uniformly lower temperature than would be the case if the injected liquid were not added. In a tested embodiment of the invention, the temperature of the gas was reduced to approximately to F., as compared to a discharge temperature of 210 to 230 F. without liquid refrigerant injection into the chamber. This high density gas at l8$ F. temperature has sufficient cooling capacity, when passed over the motor, to remove all of the motor heat and maintain the motor Within safe operating temperatures. Furthermore, the reduction in temperature of the in the compression chamber 4b permits the gas to be more easily compressed and does not to any great extent affect the efiiciency of the compressor.

As mentioned previously, the continual opening and closing of the injector port 3-1 by the end 32 of the rotor 6, causes a pulsation or vibration which results in a buzzing noise unless these vibrations or impulses are not properly damped. In order to prevent these pulses from being transmitted into the remaining portions of the system, the embodiment of the present invention incorporates an expansion chamber in the passage conducting liquid refrigerant to the injection port 31. As previously mentioned the tube 34 forms an expansion chamber 36a into which liquid refrigerant is introduced by the tube 33. It will be noted that the expansion chamber or reservoir 36;: extends upwardly into the case through the hot lubricating oil in the bottom of the case. The body of relatively hot lubricating oil surrounds the tube 34 and warms the liquid refrigerant in the expansion chamber 36a thereby causing a small amount of refrigerant to expand into gaseous form within the expansion chamber. The gas, of course, rises into the upper region of the tube expansion chamber 36a and provides a buffer zone or gas pocket which damps pulsations transmitted through the tube 36 from the injector port 31. In other words, the pocket of gaseous refrigerant in the upper portions of the expansion chamber 36a provides a certain amount of compressibility in the chamber to absorb the pulsations transmitted through the tube 36 and prevent them from being carried into the other portions of the system. Note that the lower end of the tube 36 extends into the portion of the tube 34 outside the case 2 and out of contact with the hot lubricant 24 so that liquid refrigerant is normally supplied to the end of the tube 36.

In the preferred embodiment of the invention, a capillary 37 is arranged in the liquid refrigerant supply passage in order to limit the amount of refrigerant flow th ough the passage. This prevents short 'circuiting of the evaporator of the system and effectively prevents flow of gas through the passage when the refrigerant in the condenser 22 has not been cooled sulliciently to condense into a liquid.

While in accordance with the patent statutes there has been described what at present is considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A hermetically sealed refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing the ends of said annular chamber, a rotor eccentnically rotatable within said chamber, said rtor having a peripheral surface adapted to move progressively into sealing relation with successive portions of said annular chamber, a motor having a shaft extending through one of said end walls of said cylinder for driving said rotor said chamber, a radial slot in said cylinder communicating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port communicating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge port communicating with said annular chamber for conducting hot compressed refrigerant gas from said chamber into said hermetic casing, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port in one end wall of said cylinder adapted to be covered and uncovered by the end of said rotor during the rotation thereof, and a liquid refrigerant supply means communicating at one end with said refrigerant condensing means and at the other end with said refrigerant injection port for conducting condensed refrigerant to said injection port for discharge into said chamber so that said liquid refrigerant cools said refrigerant gas being compressed in said chamber.

2. A hermetically sealed refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls closing the ends of said annular chamber, a rotor eccentrically rotatable within said chamber, said rotor having a peripheral surface adapted to move progressively into sealing relation with successive portions of said annular chamber, a motor having a shaft extending through one of said end Walls of said cylinder for driving said rotor Within said chamber, a radial slot in said cylinder communica ing with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port communicating with said annular chamber on one side of said blade for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge port eommunieating with said annular chamber on the other side of said blade for conducting hot compressed refri erant gas from said chamber into said hermetic casing, a body of lubricating oil in the lower region of said casing for lubricating said compressor, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port in one end wall adapted to be 8 covered and uncovered by the end of said rotor during the rotation thereof, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, at liquid refrigerant supply passage connecting at one end with said injection port and communicating at the other end with said refrigerant condensing means in said refrigeration system thereby to introduce condensed refrigerant into said injection port to be discharged into said chamber, said liquid refrigerant supply passage including an expansion chamber disposed in the lower region of said hermetic case and surrounded by said body of lubricating oil so that liquid refrigerant accumulating in the expansion chamber is eated by said body of oil and vaporized into gaseous form to form a compressible gas pocket for damping pulsations produced in said liquid refrigerant supply passage due to intermittent opening and closing of said injection port.

3. A hermetically sealed rotary refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing said annular chamber, a rotor eccentrically rotatable within said chamber and having a pcripheral surface adapted to move progressively into seal ing relation with successive portions of said annular chamher, a motor, a shaft on said motor extending through one of said end walls of said cylinder for driving said rotor within said chamber, a radial slot in said cylinder communicating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port com municating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber,- means including a gas discharge port communicating with said annular chamber for discharging hot compressed refrigerant gas from said chamber into said hermetic casing, a body of lubricating oil in the lower regions of said casing for lubricating said compressor and absorbing heat from said compressor, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port communicating with said chamber through one end wall of said cylinder, said injection port being located in said high pressure side of said chamber and so constructed and arranged that it is covered and uncovered by the end of saidrotor during rotation thereof, a liquid refrigerant expansion chamber having a portion thereof arranged in heat exchange relationship with said body of lubricating oil in the lower regions of said casing, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, a liquid refrigerant supply line having one end connecting with said expansion chamber and the other end connecting with said refrigerant condensing means in said refrigeration system for conducting liquid refrigerant to said expansion chamber wherein at least a portion of said liquid refrigerant is expanded into gas by the heat of said lubricating oil, and a tube extending from said injection port into the lower region of said expansion chamber for delivering liquid refrigerant from said expansion chamber into said injection port so that liquid refrigerant is injected into said compression chamber when said end of said rotor un covers said injection port.

4. A hermetically sealed rotary refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing said annular chamber, a rotor eccentrically rotatable within said chamber and having a pcripheral surface adapted to move progressively into sealing relation with successive portions of said annular chamber, a motor, a shaft extending from said motor through one of said end walls of said cylinder for driving said rotor Within said chamber, a radial slot in said cylinder communicating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port communicating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge port communicating with said annular chamber for discharging hot compressed refrigerant gas from said chamber into said hermetic casing, means for injecting liquid refrigerant into said annular chamber including an injection port communicating with said chamber through one end wall of said cylinder, said injection port being located adjacent the high pressure side of said blade and being sealed from said compression chamber by the end of said rotor except at such times during the rotation of said rotor when the pressure of said refrigerant gas in said high pressure side of said chamber is within the range of 50% to 95% of the pressure of said high pressure refrigerant gas in said case, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, and a liquid refrigerant supply passage connecting between said injection port and said refrigerant condensing means in said refrigeration system for conducting liquid refrigerant to said injection port.

5. A hermetically sealed rotary refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrig erant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing said annular chamber, a rotor eccentrically rotatable within said chamber and having a peripheral surface adapted to move progressively into sealing relation with successive portions of said annular chamber, a motor mounted above said compressor unit, a shaft extending downwardly from said motor through one of said end walls of said cylinder for driving said rotor within said chamber, a radial slot in said cylinder communieating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port communicating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge port communicating with said annular chamber for discharging hot compressed refrigerant gas from said chamber into said hermetic casing whereby said discharge gas flows upwardly over said motor for cooling said motor prior to discharging from said hermetic casing, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port communicating with said chamber through one end wall of said cylinder, said injection port being located adjacent the high pressure side of said blade and being so arranged and constructed as to be sealed from said compression chamber by the end of said rotor at all times except during the period of each cycle when the peripheral surface of said rotor is between approximately 245 and 140 in advance of the completion of the compression stroke, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, and a liquid refrigerant supply passage connected between said injection port and said refrigerant condensing means in said refrigeration system for supplying liquid refrigerant to said injection port.

6. A hermetically sealed rotary refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing said annular chamber, a rotor eccentrically rotatable within said chamber and having a peripheral surface adapted to move progressively into sealing relation with successive portions of said annular chamber, a motor mounted above said compressor unit, a shaft extending downwardly from said motor through one of said end walls of said cylinder for driving said rotor within said chamber, a radial slot in said cylinder communicating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against said peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides, means including a gas suction port communicating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge port communicating with said annular chamber for discharging hot compressed refrigerant gas from said chamber into said hermetic casing whereby said discharge gas flows upwardly over said motor for cooling said motor prior to discharging from said hermetic casing, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port communicating with said chamber through said lower end wall of said cylinder, said injection port being located on said high pressure side of said chamber and so constructed and arranged that said injector port is sealed from said chamber by the end of said rotor except at such times during the rotation of said rotor when the pressure of said refrigerant gas in said high pressure side of said chamber is within the range of 50% to of the pressure of said high pressure refrigerant gas in said case, a refrigerant condensing means in said system for condensing high pressure gaseous refrigerant within said system to a liquid, a liquid refrigerant supply passage communicating with said refrigerant condensing means in said refrigeration system and connecting with said injection port in said end wall of said compressor, said liquid refrigerant supply passage having an expansion chamber disposed in the lower regions of said hermetic casing, a body of lubricating oil surrounding said expansion chamber for vaporizing at least a portion of said liquid refrigerant therein so that pulsations caused by the opening and closing of said injection port are damped in said expansion chamber and prevented from being transmitted through said refrigerant supply passage to the remaining components of said refrigeration system.

References Cited in the file of this patent UNITED STATES PATENTS 2,247,950 Kucher July 1, 1941 2,577,107 Cooper Dec. 4, 1951 2,967,410 Schulze Jan. 10, 1961 2,988,267 Kosfield June 13, 1961 

1. A HERMETICALLY SEALED REFRIGERANT COMPRESSOR ADAPTED FOR USE IN A REGRIGERATION SYSTEM COMPRISING A HERMETIC CASING ADAPTED TO CONTAIN A HIGH PRESSURE REFRIGERANT GAS, A COMPRESSOR UNIT IN SAID CASING INCLUDING A CYLINDER HAVING AN ANNULAR COMPRESSION CHAMBER AND END WALLS ENCLOSING THE ENDS OF SAID ANNULAR CHAMBER, A ROTOR ECCENTRICALLY ROTATABLE WITHIN SAID CHAMBER, SAID ROTOR HAVING A PERIPHERAL SURFACE ADAPTED TO MOVE PROGRESSIVELY INTO SEALING RELATION WITH SUCCESSIVE PORTIONS OF SAID ANNULAR CHAMBER, A MOTOR HAVING A SHAFT EXTENDING THROUGH ONE OF SAID END WALLS OF SAID CYLINDER FOR DRIVING SAID ROTOR WITHIN SAID CHAMBER, A RADIAL SLOT IN SAID CYLINDER COMMUNICATING WITH SAID CHAMBER, A BLADE SLIDABLY POSITIONED IN SAID RADIAL SLOT, MEANS BIASING SAID BLADE AGAINST SAID PERIPHERAL SURFACE OF SAID ROTOR FOR FOLLOWING SAID ROTOR THEREBY TO DIVIDE SAID CHAMBER INTO HIGH AND LOW PRESSURE SIDES, MEANS INCLUDING A GAS SUCTION PORT COMMUNICATING WITH SAID ANNULAR CHAMBER FOR INTRODUCING LOW PRESSURE REFRIGERANT GAS INTO SAID ANNULAR CHAMBER, MEANS INCLUDING A GAS DISCHARGE PORT COMMUNICATING WITH SAID ANNULAR CHAMBER FOR CONDUCTING HOT COMPRESSED REFRIGERANT GAS FROM SAID CHAMBER INTO SAID HERMETIC CASING, A REFRIGERANT CONDENSING MEANS IN SAID SYSTEM FOR CONDENSING HIGH PRESSURE GASEOUS REFRIGERANT WITHIN SAID SYSTEM TO A LIQUID, MEANS FOR INJECTING CONDENSED LIQUID REFRIGERANT INTO SAID ANNULAR CHAMBER INCLUDING A LIQUID REFRIGERANT INJECTION PORT IN ONE END WALL OF SAID CYLINDER ADAPTED TO BE COVERED AND UNCOVERED BY THE END OF SAID ROTOR DURING THE ROTATION THEREOF, AND A LIQUID REFRIGERANT CONDENSING MEANS AND AT ONE END WITH SAID REFRIGERANT CONDENSING MEANS AND AT THE OTHER END WITH SAID REFRIGERANT INJECTION PORT FOR CONDUCTING CONDENSED REFRIGERANT TO SAID INJECTION PORT FOR DISCHARGE INTO SAID CHAMBER SO THAT SAID LIQUID REFRIGERANT COOLS SAID REFRIGERANT GAS BEING COMPRESSED IN SAID CHAMBER. 